Got a letter to tell me a BT engineer was coming to install my BTVision box. Letter said a new faceplate would be put on my master bt line box, which would mean that phone extension sockets would no longer be able to be used by a pc. My master line box is downstairs and I run my pc off an extension box in the loft. Does it mean I will have to move the pc downstairs to be adjacent to the master box? If so why?